The invention relates to downhole tools used in oil and gas wellbores. More particular, but not by way of limitation, the invention relates to downhole apparatus used to anchor a work string to a packer as well as to release the anchoring device from the packer.
In the past, packers such as the Drillable-Test-Treat and Squeeze Packers have been utilized in a number of different applications in the oil and gas industry. Other packers, such as the packer that was disclosed in U.S. Pat. No. 4,151,875 to Sullaway also contain similar features to the Drillable-Test-Treat and Squeeze Packers.
Before beginning the test, treat or squeeze function, the operator is required to sting into the top of the packer with the workstring; this is also known as anchoring into the packer. Afterwards, the anchoring apparatus is pulled out of the wellbore.
Next, it necessary to retrieve the packer from the wellbore. Basically, there are two methods utilized. The first method utilizes drilling the packer out with a Rock Bit. In utilizing this particular method, the packer is literally drilled out of the wellbore.
The second method comprises milling over a portion of the packer and utilizing an overshot to pick-out the packer.
The present invention allows for anchoring a stinger assembly to the packer and subsequently retrieving the stinger assembly. A common problem encountered while releasing from the packer is for the stinger assembly to become stuck. Once the stinger assembly becomes stuck, many times the only way of retrieving the work string is to part the work string at some point above the stinger, thus, leaving a portion of the work string above the packer in the wellbore. This situation, as will be appreciated by those skilled in the art, presents major difficulties.
Therefore, there is a need for a tool that will easily and effectively anchor a stinger assembly to a downhole packer during drill, test, treat or squeeze operations. Moreover, there is a need for a tool that will provide for an emergency release in the event the anchoring tool becomes stuck in the packer.